3,4-dichlorocoumarin bacteriostatic and fungistatic methods



Sit

weavers; use! ElZlLltbiL.

3,472}??? Patented Oct, '14, 1969 3,472,927 3,4-DICHLOROCOUMARIN BACTERIOSTATIC AND FUNGISTATIC METHODS Don R. Baker, Pinole, Mervin E. Brokke, Richmond, and Malcolm B. McClellan, San Jose, -Calif., assignor to Staulfer Chemical Company, New York, N.Y., a corporation of Delaware No Drawing. Continuation-impart of application Ser. No. 465,171, June 18, 1965. This application Mar. 20, 1968, Ser. No. 714,404

Int. Cl. A01n 9/28, 17/02; C09d /14 US. Cl. 424-45 20 Claims ABSTRACT OF THE DISCLOSURE Method of controlling the growth and development of fungi and bacteria employing 3,4-dichlorocoumarins hav= ing the general formula in which R is hydrogen, halogen or methyl, and R is hydrogen or halogen, Representative organisms controlled by this method are Aspergillus niger, Penicillz'um italicum, T richophyton mentagrophyt'es and Staphylococcus aureus. Representative compounds are 3,4,6-trichlorocoumarin; 3,4-dichloro-6-methyl-coumarin; 3,4-dichloro-6-= fluorocoumarin; 3,4 dichloro 6 a bromocoumarin; and

3,4,6,S-tetrachlorocoumarin.

wherein R is selected from the group consisting of hydrogen, halogen and methyl and R is selected from the group consisting of hydrogen and halogen. The term halo gen means the members fluorine, chlorine, bromine and iodine.

It has been found that the agents as defined above are effective against fungi and bacteria. Whereas microbiological growths on various substances cause deterioration therein by the presence of the infestation, the application ofan agent to retard this adverse growth is desired. Such substances liable to fungus include cloth, leather, paint, paper, wood and plastics, and the like. It is contemplated herein that the microb1ocidal compositions of the pres= ent invention may be effectively incorporated or applied to any of the above-mentioned substances.

For maximum. eifectiveness the active ingredients of the present invention are admixed in microbiostaticly eifec rive amount with an inert adjuvant. ln order to provide formulations particularly adapted for ready and efficient application to the material to be treated, such formulations comprise those of both the liquid and solid types as well as the aerosol type formulations. Application may be directly to the substance to be protected from fungus and bacterial growth In the pure state the active ingredient may be too effective or too potent in some applications to have practical utility. For most effective protection it is preferred to apply the materials in inti= mate contact but thoroughly dispersed on or nearly in the. surface to be protected. Therefore, the active ingredients have incorporated therewith a relatively inert agent or adjuvant as a dispersing medium, utilizing methods well known to those skilled in the art.

The formulations of this invention comprise the above defined active ingredients and a suitable material as an adjuvant therefor. Fungistat and bacteriostat compositions are advantageously formulated by first preparing a solution thereof in an organic solvent and then adding the resulting solution to water. If necessary an emulsifying agent may be employed. The formulations may also be incorporated into solid carriers such as clay, talc, pumice and the like. They may also be dissolved in lique fied gases such as fluorochloroethanes or methyl chloride and applied from aerosol bombs containing the solution.

it should be noted that formulations of this invention may also include adhesive agents, indicators, and other active microbiocidal ingredients. Such other ingredients may be supplementary insecticides, fungicides, bacterio cides, nematocides or selective herbicides.

Since the amount of active agent of the present in vention which is employed will vary with the microbio cidal effect sought, the utility of the treated material, the type and dimensions of the material treated, it is evident that no rigid limits can be set forth on the quantity tre quired. Determination of the optimum effective concen tration for a specific performance is readily conducted by routine procedures, as will be apparent to those skilled the art.

The compounds of the present invention are of special value in application, for example, to textiles to impart to the textile protection against mildew or other fungus or bacterial attack. The compounds of this invention give excellent control in controlling the growth of fungi upon cellulous material, for example, cotton cloth, Likewise, the compounds have microbiological activity when applied to foliage. The compounds are conveniently applied to textiles by -luti-ng'-this"solud'fi with water to the desired concentra= tion. The textile is then rinsed in the solution and allowed to air dry. Effective amounts of the compounds in the range of 1 part per million to 5 percent can be deposited upon the textile in this manner. Because of the low con centrations in which the compounds are effective as microbiostats, the compounds can be applied to light col= ored or white fabrics with no impairment of the color of the textile.

The following examples illustrate the employment of the method of the present invention for the effective con trol of fungi and bacteria.

EXAMPLE 1 Fungicide in vitro evaluation The candidatecompounds are tested against growing fungi in artificial media. Nutrient agar, Emmons agar or potato dextrose agar are used as the artificial media for the various test species.

The compounds are diluted with melted agar to give concentrations of 50, 10, 5 and 1 parts per million (p,p.m.). The agar thus treated is allowed to solidify in sterile Petri dishes. Certain of the nutrient agar plates season still gijsolvip g tl lg ggmp lllliilln tleloneaand11k are inoculated with Aspergillus niger cells. Potato dextrose agar is also used as an artificial medium for Aspergillus niger cells and for Penicillium italicum. Emmons agar is used as the artificial medium for Trichophyton mentagrophytes. The Petri plates are held at either room temperature for one week or 30 C. for five days in order to allow the organisms to grow, at the end of which time the results are observed and noted. Table I contains the data obtained in this manner. The minimum inhibitory concentration for complete control is given for representatlve compound.

TABLE I.-IN VITRO PLATE TEST Minimum inhibitory conc. 100% control (p.p.n1.)

Holding T. Menta- Compound temp. C.) A. niger P. italt'cum groplzytes 3,4,6-trichlorocoumarin Room temp. iiidichlorocou mariu Room temp. 3,4dichloro-6- methylcoumarin... Room temp. 3,4,dichloro-6- fluorocoumarin. s a 30 1 I 5 3,4,dichloro-6- bromocoumarin 30 1 1 l 3,4,6,7-tetracl1lorocoumarin..... 30 5 l 3,4,6-trichloro-T metl1ylcoumarin 30 50 2 (50) 3,4,6,8-tetrachloro coumarin- 30 50 1 l 3,4,6-trich1oro 8- methyleoumarinfl, 30 5 10 1 In nutrient agar. 2 Partial control at this concentration,

The compound 3,4,6-trichlorocoumarin was also tested in Emmons agar against Pullularz'a pullulans. A similar method was employed, as described above, wherein the compound was incorporated in the dissolved agar and cells of the test organism were added to the solidified agar. The compound thus tested gave partial control of .Pullularia pullulans at 5 ppm. 3,4,6-trichlorocoumarin was also effective in partial control of Penicillium at 5 ppm, complete control of bean rust at 1000 ppm. and 95% control of mildew on pinto bean plant at 1000 ppm.

EXAMPLE 2 Textile treatment test In order to test the applicability of the present method of inhibiting microbiological development, cotton fabric was treated therewith and the resulting inhibiting effect investigated. The test was performed accOrding t the following procedure.

The candidate compound was dissolved in sufficient acetone to give a 1% solution. From this solution was taken 0.5 ml. and this was added to 500 ml. of tap water to ive a resulting concentration of 10 ppm. of the test compound in water. The solution of water and test chemical was agitated for a short period of time. Following the preparation of the rinsing solution the fabric samples were added. Four one-inch square pieces of 8 oz. white cotton duck was used as the test fabric. The fabric samples were agitated gently for five minutes in the test solution. All of the cloth samples were then removed and allowed to air dry until yet damp.

Sterile, melted and cooled nutrient agar was inoculated with respective selected test organisms by streaking the a ar plates with cells of the organisms. Selected as representative test organisms were Aspergillus niger for fungi and Staphylococcus aurcus for bacteria. The damp-dry treated fabric samples were placed on the inoculated agar and incubated.

When 3,4,6-trichlorocoumarin was used as the test compound in the above-mentioned test procedure, the test plate inoculated with Aspergillus niger cells was in cubated at room temperature for three days, after which time a zone of inhibition of 21 mm. had formed. around ll the fabric sample. The nutrient agar plate inoculated with Staphylococcus aureus cells and containing a piece of treated cloth was incubated for 24 hours at 37 C., after which time a zone of inhibition of 6 mm. had formed around the treated fabric sample.

It should be noted that fabric samples containing there on effective quantities of microbiostatic agent exhibited a zone of inhibition comprising an area surrounding the sample wherein bacterial growth was not observed.

EXAMPLE 3 Paint test The test paint formulation is made up as follows: Titanium dioxide, anatase chalking g 12.5 Co-fumed, 35% leaded zinc oxide g 42.5 Magnesium silicate g 30.0 Refined linseed oil g 31.8 Z-2 linseed oil gm 9.2 Mineral spirits g 15.0 Cobalt naphthenate, 6% mg 200 Manganese naphthenate, 6% mg 100 Lead naphthenate, 24% mg 400 Sample of the above formulation is used as a control sample. In addition, a sample is prepared to which 300 mg. of 3,4,6-trichlorocoumarin is added. Each of the above samples is placed in separate 5 /2 oz. stainless steel mills each having 30 g. of Ms" stainless steel balls added. The mills are shaken on a paint shaker for 2 /2 hours. The paint samples are each of a Hegman gauge of 6. One milliliter sample from each of the prepared paints is painted on strips of fiberglass tape, ten inches by three fourths inches and 0.007 inch thick, that are previously desized at 700800 F. until all of the carbon was removed.

The paint strip samples are allowed to dry at room temperature for 2 weeks. At the end of this time each sample is cut into three parts. One part is soaked in running water for 72 hours. Another part is weathered in a weatherometer for 300 hours and the other part is used as a control. Each of the treated parts is cut into one inch long strips and placed on hardened steril ASTM nutrient salts agar (60 ml.) in large Petri dishes. Each dish is inoculated with a water suspension of Aspergillus niger, Penicillz'um sp., Pullularia pullulans and two unidentified cultures. The mixed cultures are incubated at 30 C. and relative humidity and are examined at Weekly intervals. The re ults are as follows:

TABLE Ill-GROWTH OF FUNGI ON PAINT SURFACE 1 Week 2 weeks 3 weeks 4 weeks Paint with no biocide:

Untreated strip Water soaked strip- Weathered strip Paint with 3,4,6-dichl0rocoumarin:

Untreated strip Water soaked stri Weathered strip 0=N0 growth. +=Slight growth. ++=Moderate growth. Heavy growth.

5,. What is claimed is: l. The method of controlling the growth of bacteria and fungi comprising applying thereto an eifective amount of a compound having the formula wherein R is selected from the group consisting of hydro gen, halogen and methyl and R is selected from the group hydrogen and halogen.

2., The method according to claim 1 in which R is 6- chloro and. R is hydrogen.

3.. The method according to claim 1 in which R is hydrogen and R is hydrogen.

4. The method according to claim 1 in which R is 6- methyl and R is hydrogen.

5. The method according to claim 1 in which R is 6- bromo and R is hydrogen,

6, The method according to claim 1 in which R is 6- fiuoro and R is hydrogen.

7 The method according to claim 1 in which R is 6- chloro and R is 8-chloro.

8. The method according to claim 1 in which R is 6- chloro and R is S-methyl.

9. A composition effective against bacteria and fungi comprising an inert aerosol bomb liquified gas having dissolved therein as the effective ingredient a compound having the formula wherein R is selected from the group consisting of hydrogen, halogen and methyl and R is selected from the group hydrogen and halogen.

10, A composition according to claim 9 in which R is 6-chloro and R is hydrogen.

11. A composition according to claim 9 in which R is hydrogen and R is hydrogen.

12.. .A. composition according to claim 9 in which R is 6-methyl and R is hydrogen.

13. A. composition according to claim 9 in which R is ti-hromo and R is hydrogen.

14, A. composition according to claim 9 in which R is fi-fluoro and. R is hydrogen.

15. A composition according to claim 9 in which R is 6-chloro and R is 8-chloro.

16. A composition according to claim '9 in which R is 6-ch1oro and R is 8-methyl.

17. The method of controlling the growth of fungi in paint comprising incorporating therein a fungicidally effective amount of a compound having the formula m fi wherein R is selected from the group consisting of hydrogen, halogen and methyl and R is selected from the group hydrogen and halogen.

20. The method of claim 19 in which R is chlorine and R is hydrogen,

References Cited UNITED STATES PATENTS 1,995,247 3/1935 Haring 424-281 XR 2,887,495 5/1959 Wilson 260-3432 OTHER REFERENCES A.P.C. No. 188,058, June 1943. Dorr et a1. I.A.'C.S. 81: 2266 (1959),

S. K. ROSE, Primary Examiner US. Cl. X.R. 

